:root{
    /* 自定义变量 */
    --content-height-2 :calc( 100vh - 4.2rem);
    --content-height-without-header:calc( 100vh - 20px - 3rem );
}
.button{
    font-size: .8rem;
}
.course-detail-container {
    flex:1;
    height: var(--content-height-2);
    display: flex;
    gap: 1em;
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.1);

}

.sidebar {
    display: flex;
    height: var(--content-height-2);
    flex-direction: column;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    text-align: left;
}


.content-container {
    flex: 1;
    height: var(--content-height-2);
}


.loader-tech {
    position: relative;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: #0d1b2a;
    display: flex;
    justify-content: center;
    align-items: center;
}

.loader-tech::before,
.loader-tech::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 3px solid #00b4d8;
    opacity: 0;
    animation: pulse-tech 1.8s infinite;
}

.loader-tech::after {
    animation-delay: 0.6s;
}

@keyframes pulse-tech {
    0% {
        width: 40px;
        opacity: 0.8;
    }
    100% {
        width: 100px;
        opacity: 0;
    }
}
.loader-nature {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    position: relative;
}

.ripple {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    border: 2px solid #d3f6fd;
    opacity: 0;
    animation: ripple-animation 1.5s ease-out infinite;
}

.ripple:nth-child(1) {
    animation-delay: 0s;
}

.ripple:nth-child(2) {
    animation-delay: 0.3s;
}

.ripple:nth-child(3) {
    animation-delay: 0.6s;
}
@keyframes ripple-animation {
    0% {
        transform: scale(0);
        opacity: 0.8;
    }
    100% {
        transform: scale(1.5);
        opacity: 0;
    }
}
@media screen and (max-width: 768px) {

    .course-detail-container{
        flex-direction: column-reverse;
        height: calc( var(--content-height-without-header) - 10px);
    }
    .sidebar-container{
        position: sticky;
        bottom: 0;
    }
    .sidebar {
        height: auto;
        width: 100%;
        max-height: 30vh;
        max-width: 100%;
    }
}

.border-bottom-foreground {
    border-bottom: 1px solid var(--primary-color);
}

.nav-item,.current-title{
    max-width: 250px;
    overflow-x:scroll;
}
.nav-item::-webkit-scrollbar,.current-title::-webkit-scrollbar{ 
   width: 8px;
   height: 8px;
}
.nav-item::-webkit-scrollbar-thumb,.current-title::-webkit-scrollbar-thumb{ 
    background: var(--primary-color);
}
@media screen and (max-width: 768px) {
    .nav-item,.current-title{
        max-width: 100%;
    }
    .nav-item::-webkit-scrollbar,.current-title::-webkit-scrollbar{ 
        width: 0;
        height: 0;
    }
}